As a prelude to the problem
of divine action and quantum physics, William R. Stoeger explores the
epistemological and ontological implications of quantum physics. Clearly a
discussion of divine action in nature requires our confidence that scientific
theories actually represent processes and features of the world that are, in
some ways, independent of how we know them. Using these theories, we may then
be able to constrain our description of divine action in important ways. But to
gain confidence in our theories, we must first sift through their interpretations,
assessing them in terms of their adequacy and fruitfulness; only those that
survive this process will warrant further consideration. What then constitutes
a canon of adequacy for our assessment?

Stoeger responds first by
noting that there are several levels of interpretation involved: i) basic
interpretation at the level of the physical theory itself (e.g., the
probabilistic interpretation of the square of the wavefunction); ii)
consistency and coherence both within the theory, and iii) with other physical
theories (e.g., with special relativity); and iv) epistemological and
ontological interpretations by which quantum theory may give us knowledge of
the underlying reality. Clearly levels (i) - (iii) constrain level (iv) without
determining it completely. Using levels (iii) and (iv), Stoeger argues that we
can exclude both hidden-variable and other strongly deterministic
interpretations of quantum theory. Next, he proposes a principle of parsimony
in which we minimize our assumptions about what reality is like, allowing the
results of quantum physics to speak for themselves even if the result is
counterintuitive and puzzling. That our interactions with the quantum level are
recalcitrant and resistant suggests that we are dealing with aspects of the
world independent of our measurement of it. We may not have any direct
knowledge of the underlying states which produce the phenomena we measure, but
our experimental and theoretical knowledge place significant constraints on the
properties these underlying entities can have. This assumption is warranted
since the models we construct successfully predict and explain other phenomena.
Stoeger relies on Ernan McMullins emphasis on retroduction to support these
points. Still, he acknowledges that there may be many significant features of
quantum reality that completely escape our detection. Some of these may never
be knowable even in principle, while reality for us may have features that
are not functions of the actual underlying features of the world. Stoegers
essential metaphysical presuppositions, then, are the principle of sufficient
reason (what we observe in some way points to an underlying cause) and the
principle of relationality (the reality with which we interact is a part of a
network of relations with processes and objects at other levels of the world).

Stoeger then briefly
describes several key features of quantum physics, including nonseparability,
quantization, objective uncertainty, complementarity, objective chance,
correspondence, entanglement, measurement, and decoherence. Returning to his
criteria for choosing an interpretation, Stoeger notes that the family of
Copenhagen-like interpretations (including the consistent-histories approach)
involves most of these features and is by far the most satisfactory
interpretation, compared with hidden-variable and many-worlds interpretations.
Thus our indirect knowledge of reality is weakly objective: an independent
reality exists and is manifest to us through our interactions with it, but we
cannot assess our knowledge of it from these observations. Regarding the
question of the epistemic and ontological status of the laws of nature, Stoeger
sees these laws as but imperfect and incomplete descriptions of those that
obtain in nature. Moreover, these laws are descriptive, not prescriptive.

Several implications for
divine action follow from this. Gods universal creative action is realized
behind the veil of natural laws, and it appears in the form of these laws.
Isolated cases may seem to violate these laws, and Gods action may occur at
the level of consciousness and personal relationships. Special divine action
may involve top-down influences on matter and thus transcend science. Divine
action, as acts of love and care, may be taken to be interventions only if we
assume that the laws hold absolutely under all circumstances. The key problem,
particularly compared with that of human agency, is our lack of understanding
of how an immaterial God can act on the material world.